When I tested GC and processed an order on my website, the shipping rate of all delivery methods were "zero"

I have activated the GC account and set up all the available FedEX delivery methods using carrier-calculated option on Google. At my website, I set up the GC module (osCMax v1.4beta1.2) and applied default value "zero" for real time shipping. Is there a way to fix this? (the original paypal checkout works fine) Hope someone can help us with instructions.

Thank you so much!

PC Bees